The present invention relates in general to the art of earth boring and more particularly to a locking apparatus for an earth boring cutter or stabilizer.
The rolling formation contacting member of an earth boring bit or drill string stabilizer must be easy to assemble, must lock firmly in place during operation and should be easy to disassemble. The bit or stabilizer generally operates under severe conditions and is subject to the corrosive forces of the drilling environment. In addition, the bit or stabilizer must be adapted to withstand heavy loading and high torque.
The rotatable cutters of an earth boring bit are often positioned between a pair of support arms extending from the body of the bit. A journal assembly extends between the support arms and secures the cutter to the main body. The cutters have a useful lifetime that is much shorter than the lifetime of the bit. Consequently, means must be provided to allow the cutters to be changed. The heavy loading and high torque encountered during the drilling operation, as well as the corrosive drilling environment, complicates the problem of providing a cutter that will remain firmly in place during drilling yet may easily be changed.